Make recently_changed_packages_activity_stream a helper

recently_changed_packages_activity_stream was an @Property of the
HomeController, but it wasn't working, accessing the property just
returned a property object e.g. <property object at 0x7f7210087e68> not
the HTML string as desired.

I think this is because the @Property was declared inside a method, and
properties only work at class-level.

The @Property cannot simply be moved to class level because it uses
`context`, a param of the index() function it was defined in.

Instead move recently_changed_packages_activity_stream into helpers.py,
where any template (not just the front page) can access it like this:

    {{ h.recently_changed_packages_activity_stream() }}

dashboard_activity_stream is already done the same way (but other
activity streams are not).

This means any existing home/index.html templates that were accessing
recently_changed_packages_activity_stream as an attribute of the
template context itself, will no longer work. However, apparently they
weren't working anyway.

ckan/controllers/home.py

@@ -104,11 +104,6 @@ def index(self):
             if msg:
                 h.flash_notice(msg, allow_html=True)
 
-        @property
-        def recently_changed_packages_activity_stream():
-            return ckan.logic.action.get.recently_changed_packages_activity_list_html(context, {})
-        c.recently_changed_packages_activity_stream = recently_changed_packages_activity_stream
-
         # START OF DIRTYNESS
         def get_group(id):
             def _get_group_type(id):

ckan/lib/helpers.py

@@ -1190,6 +1190,13 @@ def dashboard_activity_stream(user_id):
                                                             {'id': user_id})
 
 
+def recently_changed_packages_activity_stream():
+    import ckan.logic as logic
+    context = {'model': model, 'session': model.Session, 'user': c.user}
+    return logic.get_action('recently_changed_packages_activity_list_html')(
+            context, {})
+
+
 def escape_js(str_to_escape):
     '''Escapes special characters from a JS string.
 
@@ -1381,6 +1388,7 @@ def resource_preview(resource, pkg_id):
            'add_url_param',
            'groups_available',
            'dashboard_activity_stream',
+           'recently_changed_packages_activity_stream',
            'escape_js',
            'get_pkg_dict_extra',
            'get_request_param',